> If no computer models were used, how much could the basic scientific understanding of climate change differ?

If no computer models were used, how much could the basic scientific understanding of climate change differ?

Posted at: 2015-03-12 
Without computers it would be pretty much impossible to construct such datasets as GISS or HaDCRUT4, because the raw data, which denialists love to talk about so much is the data from thousands of individual weather stations.

But, as far as computer simulations go, their absence would actually have no impact on the basic understanding of climate change. The fact that carbon dioxide is a greenhouse gas is not something we get from computer simulations. It is programmed into computer simulations.

I think it's disingenuous to say that it wouldn't change things and I think some people have argued their case with the deliberate intention of trying to close off the skeptics' arguments. It's easy to say 'nothing would have changed therefore shut up about the models'! The reality, I suspect, is not that simple.

If you wanted to properly analyse the absorption of sunlight by the earth's surface and the conversion of that energy into heat, then you would have to do a complicated quantum mechanical calculation involving the fine structure constant. Which is mathematically impossible on a planetary scale. So, instead, you'd use empirical constants such as the reflectivity and emissivity of different materials. You don't model every atom in the atmosphere, but volumes of atmosphere and apply fluid dynamics laws to those volumes.

The point is that our models of the climate contain many such 'approximations'. And, as we do with friction or other complicated systems (coefficients depending on the materials), we insert values to weight the different factors we think affect our climate. Different models weight those factors in different ways. Different models include some aspects and not others. Different models use different 'approximations' of those complex physical laws that we cannot computationally apply on extremely high resolutions (because the processing power simply isn't available to us yet!).

So, for example, if we find Model A doesn't do a good job of matching temperatures from, say, 1900 to 1940, but Model B does then we look at why that is the case. Is it because Model B included something that A didn't? Was there a difference in the 'approximations' those models used? And if so, then that might raise a scientific question of the form 'how significant was factor X'? And that then prompts other scientists to devise an experiment that might give an answer that can be used in subsequent models.

The purpose of the models is not simply to predict what will happen in the future. The purpose of models is to sit with experiments in a constant circle. Model predicts this, experiment shows that, model is changed, experiments disagree, model is tweaked and predicts the other, experiment sees if that is the case. This is how we've done science since Newton.

The one thing that we can say is that all the models so far and all the experiments conducted to date paint a coherent picture - something changed around the 1970s in terms of the processes affecting our climate. That could be:

a. Some 'natural' factor that hasn't been included yet

b. Some existing factor that hasn't had its significance correctly input into the models

c. The cumulative effect of anthropogenic greenhouse gases

The last, when included in the models, does a reasonable job of modelling the temperatures and is consistent with experimental evidence showing increases in concentration of anthropogenic greenhouse gases. That doesn't mean the other two are impossible as explanations, merely increasingly improbable as time goes by and no solution involving those is found.

For all the talk about models, the skeptics have been unable to produce a model of their own that models the temperatures over the past 100 years, models the rise since the 1970s, or even a short-term model that explains the 'pause' they continually harp on about. It's all very well saying 'it's changes in solar activity that caused the pause' ... do the maths, and show us how the energy flux changed, show us the satellite data confirming it, and show us the temperatures that would have resulted. You get zero science credibility points for talk rather than action. And we've waited 30 years for you to get your act together.

Without computer models, we would still be able to see that Greenland has a net loss of ice in the last 10 years. Antarctica is becoming less arid, as to let more snow and growth of in the interior of the continent in height, but with its perimeter shrinking with time. These are things we can measure in real time. We also know of the ice-albedo feedback loop, the effects of warmer ocean temperatures, that even glaciers, even tropical glaciers in the Andes are melting away (the tropics clearly being less effected by any climate change). We just would be less familiar with how changes in climate may play out in the coming decades. But the problem doesn't lie in the computer models. It stems from ignorance and an unfortunate political and economic pounce on "green living" which turned many people who saw through the lame attempts from people trying to gain power from global climate change. That doesn't take away from the fact that it's there, but it has confused some people into completely ignoring any man-made sources of what we could be facing in the future.

People who have little to no understanding of science and blindly follow these sorts of "news" reportings and incorporate such ideas into their world view should have absolutely no say in such matters. Unfortunately, because people who should have absolutely no say in such matters actually exist, we run into this crazy problem of elected officials who are governing us with the shared mindsets of the fools who brought them to their positions.

I particularly 'liked' Cyclops recent rant/question titled "The warmunists of the church of climatology embrace bogus science done by computer models based on half-assed theories. Should we instead be more concerned about an asteroid collision?".

It's a pity I can't answer (he's blocked me now too, apparently) because his 'question' is a good example of how truly misguided and stupid some science deniers are. How does Cyclops (or any other of the participating deniers) suppose the trajectory of asteroids get calculated? How does he think potential impact zones, loss of life and damage are estimated? Pen and paper?

Their level of ignorance is astonishing.

Get yo' words spelt correctly . How you gonna measure global events in real time , snail mail ? Regarding models , dig this , Thor Heyderahl , writer of " Kon Tiki " said "if you make a model of the Earth , the size of a football , one can't find a paint thin enough to represent the Oceans ! " and seawater soaks up heat and moves that energy to cold places ! Just because some folk understand 'puters and make money from complications , doesn't mean global ramifications of say ; genocide of Plains Redskins killing buffalos and substituting root pulling cattle, led to dust bowls and goons jumping out of windows on Wall Street are always recognised.

computer and climate? computer is just a recorder of climate. i think we shouldn't relay on computer to much. maybe i just misunderstand your question.

Computers are used ubiquitously nowadays but there are not, for example, thousands of fake questions in the Finance section of YA trying to lamely suggest that because Wall Street uses computer models that therefore the stock market is "bogus."

Models, with or without computers, are also central to science.

But, is there even the slightest substance to the rote anti-science denier regurgitation amounting to (see this Limbaughian gibberish of a "question": http://answers.yahoo.com/question/index?qid=20131107200628AAc8VKK) "we cannot predict the future therefore discussions of how things change over time is a hoax"?